A backlight source is a light source that is disposed in the back of a Liquid Crystal Display, which has an important impact on the display effect of the Liquid Crystal Display. According to the different light sources employed by the backlight source, the backlight source can be divided into Electroluminescent Light, cold Cathode Fluorescent Lamp (CCFL) and Light Emitting Diode (LED) light source. According to the different installation position of the light source, the backlight source can also be divided into an edge-lighting type and direct-lighting type.
The traditional edge-lighting type LED backlight source mainly includes a LED, a light guide plate, a quantum dot film and a prism film. LED is located at one side of the light guide plate, the quantum dot film is sandwiched between the light guide plate and the prism film. Light emitted by a LED changes the emitting direction by passing through the light guide plate, and then passes through the quantum dot film and the prism film to emit. The role of the quantum dot film is to provide quantum dots, the quantum dots can emit light upon excitation with light emitted by the LED. Light emitted by quantum dots and the LED can form white light after mixing, thereby enhancing the display effect of a Liquid Crystal Display.
The inventors found the following technical problems existed in the prior arts during the process of achieving the present disclosure.
When light emitted by a LED is incident on a quantum dot film in a vertical direction after passing through a light guide plate, the optical path of the light is the shortest in the quantum dot film; Light will excite a certain number of quantum dots to emit light. While when light emitted by a LED is incident on a quantum dot film in a non-vertical direction after passing through a light guide plate, especially in the direction deviating relatively far from the vertical direction, the optical path of the light is relatively long in the quantum dot film, light will excite relatively more quantum dots to emit light. Then the color gamut of the picture displayed by a Liquid Crystal Display is smaller than the color gamut of the picture displayed when light is incident on the quantum dot film in the vertical direction, and the phenomenon of the color deviation of the wide viewing angle occurs.